On Thursday, October 27, 2005, a weak surface boundary extending from near Uvalde to Cotulla to Kingsville, separated warm moist air over the Rio Grande plains from drier and slightly cooler air across southeast Texas.  In addition, the base of an upper level trough moved across south-central Texas Thursday afternoon.  This feature provided some large scale lift and ushered colder mid and upper level air across the region, which destabilized the atmosphere as surface temperatures rose into the upper 70s and low 80s.  The surface high pressure center to the northeast provided a moderate easterly flow near the surface which quickly turned southeast to south above the surface.  In addition, modest westerlies existed in the mid and upper levels of the atmosphere.  This vertical wind shear together with the modestly unstable atmosphere provided an environment favorable for rotating thunderstorms.  During the afternoon scattered thunderstorms began to develop in the warm, unstable airmass across the Rio Grande Plains and deep south Texas.  A few thunderstorms, which developed along the weak surface boundary, gained strength and became severe as they moved southeast along the boundary. The event began as a strong storm developed near Zavala/Frio Counties in the western hill country.  This storm quickly became severe as it crossed into La Salle County, gaining supercell characteristics as it traveled along the surface boundary across La Salle and southwest McMullen counties.  Reports of dime to penny size hail and 60 mph wind gusts were received by storm spotters just south of Dilley in northern La Salle County.  No storm reports were received in McMullen County, likely because of the lack of population and roadways through the area where the severe storm tracked. The storm tracked through southwestern McMullen and northern Duval Counties, maintaining its strength while exhibiting strong convergence in the middle portions of the storm (MARC signature) at times.  Another storm pulsed up across north-central Jim Wells County before weakening southeast of Alice. Outflow from this storm, as well as moderate to strong east to northeast flow across the Coastal Bend and southeast Rio Grande Plains, may have contributed to an enhanced area of wind shear across Duval County.  As the La Salle/McMullen supercell thunderstorm moved into this area across Duval County, the thunderstorm circulation steadily deepened and strengthened.  Doppler radar showed and a reflectivity notch developing right along the above mentioned boundary associated with the increased storm rotation. A Tornado Vortex Signature developed near this notch prompting a tornado warning.  Prior to the tornado warning, severe thunderstorm warnings were present through the life of this storm due to strong hail signatures and severe straight line wind indications seen on doppler radar. A NWS storm survey team toured Duval and Jim Wells counties and concluded the damage was largely a result of straight line winds from a long track supercell thunderstorm.  However, it cannot be ruled out that an isolated tornado was embedded in the storm. Wind speeds were estimated to range from 80 to 100 mph which is equivalent to an F1 tornado on the Fujita damage scale.  The damage swath, which was approximately 4 to 5 miles in width and over 40 miles in length, stretched from just east of Freer to near  Premont. Broken windows and roof shingle damage on all properties was observed on the northwest side, which indicated straight line wind damage and the wind blowing from the northwest to the southeast.  American Electric Power (AEP) crews on the scene reported that roughly 100 power poles were knocked down across Duval and Jim Well counties.  The NWS team assessed that all poles were blown in the downwind direction to the southeast. Visible damage began near Highway 44 and FM 3196, where roughly half a dozen power poles were split in half.  The damage continued in the community of Rosita in which houses experienced minor damage.  Hail was also reported up to 4 inches in depth.  Indications that flash flooding occurred on Rosita Creek was observed.The storm appeared to strengthen as it approached the northeast side of Benavides and the town of San Jose.  Two mobile homes were destroyed and tree limbs were broken with all damage lying in a southeast direction.  Fifteen homes were damaged in San Jose with window and roof damage on the northwest side, which again indicates the wind blew from the northwest to the southeast. Just southeast of San Jose, near the intersection of FM 2295 and FM 1329 and extending south all the way to Rios, tree limbs and power poles were broken and lying in a southeast direction.  An empty grain silo was also destroyed and a newly framed home was blown off its foundation. In extreme southwest Jim Wells county near the intersection of county road 428 and 716, a large empty grain silo was destroyed and lying in the middle of the roadway.  Power poles were knocked down, 5 homes were damaged, and 1 garage was completely destroyed.  Again all the visible damage was lying in a southeast direction. Eye witness reports indicate that nickel to quarter sized hail covered the ground up 4 to 6 inches deep along the entire storm track.

Thunderstorm Wind in LA SALLE, TEXAS
From 27-OCT-05 13:40:00 to 27-OCT-05 13:40:00 (CST)
Location: COTULLA MUNI ARPT
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

Gusts were estimated by trained spotter 4 miles north of Millet, or just south of Dilley, on I-37.

Thunderstorm Wind in DUVAL, TEXAS
From 27-OCT-05 16:09:00 to 27-OCT-05 16:09:00 (CST)
Location: FREER
Magnitude: 60 EG
Reported by: LAW ENFORCEMENT

Telephone poles reported blown down along Highway 16, north of Freer.  Winds were estimated between 60 and 80 mph.

Hail in DUVAL, TEXAS
From 27-OCT-05 16:09:00 to 27-OCT-05 16:09:00 (CST)
Location: FREER
Magnitude: 0.88 
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in DUVAL, TEXAS
From 27-OCT-05 16:45:00 to 27-OCT-05 16:45:00 (CST)
Location: FREER
Magnitude: 70 EG
Property damage: 1K
Reported by: NWS STORM SURVEY

NWS storm survey observed roughly half a dozen power poles broken in half along FM 3196 just north of Highway 44.  The power poles were lying towards the southeast suggesting straight line winds.  Winds were estimated between 70 and 80 mph.

Hail in DUVAL, TEXAS
From 27-OCT-05 16:30:00 to 27-OCT-05 16:30:00 (CST)
Location: FREER
Magnitude: 1.00 
Reported by: LAW ENFORCEMENT

Quarter size hail observed to be 4 inches deep in some spots along Highway 44.

Thunderstorm Wind in JIM WELLS, TEXAS
From 27-OCT-05 18:05:00 to 27-OCT-05 18:05:00 (CST)
Location: PREMONT
Magnitude: 65 EG
Reported by: NWS STORM SURVEY

18 wheeler was flipped on its side on U.S. 281 just south of Premont.

Thunderstorm Wind in DUVAL, TEXAS
From 27-OCT-05 17:20:00 to 27-OCT-05 17:20:00 (CST)
Location: SAN JOSE
Magnitude: 87 EG
Property damage: 150K
Reported by: NWS STORM SURVEY

An NWS storm survey concluded straight line winds severely damaged roughly 15 homes, a community center and church.  Nearly all the damage was observed on the northwest sides of the structres with debris scattered to the southeast.  Two mobile home were completely destoyed, with one man injured that was inside one of the mobile homes.  The two mobile homes that were completly destroyed were oriented north-northeast to south-southwest, perpendicular to the northwest to southeast straight-line winds observed on radar.  The damage from the two mobile homes was thrown to the southeast roughly 20 yards.  In addition numerous large trees and power poles were uprooted and broken, all lying to the southeast direction.  Several vehicles were also damaged by the uprooted trees and debris from homes.  Winds were estimated between 80 and 100 mph.

Thunderstorm Wind in DUVAL, TEXAS
From 27-OCT-05 17:25:00 to 27-OCT-05 17:25:00 (CST)
Location: SAN JOSE
Magnitude: 87 EG
Property damage: 40K
Reported by: NWS STORM SURVEY

An NWS storm survey observed straight-line wind damage along a 4 to 5 mile path from the intersection of FM 1329 and FM 2295 southward.  Numerous large limbs on mesquite trees had been snapped as well as power lines and poles blown down.  An empty grain silo was also destoyed and a newly framed house was blown of its foundation.  All damage was lying towards the southeast direction.  Winds were estimated between 80 and 100 mph.

Thunderstorm Wind in JIM WELLS, TEXAS
From 27-OCT-05 18:00:00 to 27-OCT-05 18:04:00 (CST)
Location: PREMONT
Magnitude: 78 EG
Property damage: 40K
Reported by: NWS STORM SURVEY

An NWS storm survey observed evidence of straight line wind damage in extreme southwest Jim Wells county, in and near Premont.  A large empty grain silo was destroyed near CR 428 and CR 716 and lying in a southeast direction across the roadway.  Power poles were knocked down and large limbs snapped off trees along CR 716 just west of Premont.  Five homes along CR 716 were also observed to have minor window and roof damage.  On garage was completly destoyed, with the debris blown downwind to the southeast.  Large limbs of trees were also snapped in Premont.  Winds were estimated between 70 and 90 mph.

Hail in DUVAL, TEXAS
From 27-OCT-05 17:20:00 to 27-OCT-05 17:20:00 (CST)
Location: SAN JOSE
Magnitude: 1.00 
Reported by: NWS STORM SURVEY

Quarter size hail was 4 to 6 inches deep in San Jose.  Nearly 20 hours later drifts of dime size hail was observed still to be on the ground by an NWS storm survey team.

Thunderstorm Wind in DUVAL, TEXAS
From 27-OCT-05 17:10:00 to 27-OCT-05 17:10:00 (CST)
Location: SAN DIEGO
Magnitude: 78 EG
Property damage: 5K
Reported by: NWS STORM SURVEY

An NWS storm survey observed roughly a dozen power poles broken, as well as large branches of mesquite trees down, along a 4 to 5 width of Highway 359 between San Diego and Benavides.  All the power poles were blown down towards the southeast suggesting straight line wind damage.  Winds were estimated between 80 and 100 mph.

Thunderstorm Wind in DUVAL, TEXAS
From 27-OCT-05 16:47:00 to 27-OCT-05 16:47:00 (CST)
Location: ROSITA
Magnitude: 70 EG
Property damage: 5K
Reported by: NWS STORM SURVEY

A NWS storm survey observed minor damage to homes in Rosita, which included windows blown out and roof damage on the northwest side of structures.  Powerlines and tree limbs were also observed down, lying in a southeast direction.  Damage suggested straight line winds.  Winds were estimated between 70 and 80 mph.

Hail in DUVAL, TEXAS
From 27-OCT-05 16:47:00 to 27-OCT-05 16:47:00 (CST)
Location: ROSITA
Magnitude: 0.88 
Reported by: NWS STORM SURVEY

Nickle size hail was observed 4 inches deep be residents in Rosita.

Flash Flood in DUVAL, TEXAS
From 27-OCT-05 17:00:00 to 27-OCT-05 18:00:00 (CST)
Location: ROSITA
Reported by: NWS STORM SURVEY

An NWS storm survey that was docummenting wind damage in Rosita observed indications that a flash flood occurred along Rosita Creek in the town of Rosita.  Residents also confirmed that the low water crossing over the creek became impassable.